206
I. Hisaki et al.
Fig. 11.7 C 3 PIs applied to construct HOFs
11.3.1 A Series of Cyclic π-Conjugated Systems
with Different Sizes of Macrocycles
C 3 PIs Tp, T12, T18, and Ex give H-HexNets structures via complemental H-bonding
between the carboxy groups (Fig. 11.8a–d) [55]. In the H-HexNet sheet, three kinds
of pores are formed. Void I has width of approximately 8 Å is formed within the PhT
motif. Void II has a non-regular hexagonal-shaped aperture. Its dimension is varied
depending on the size of the core of C 3 PIs: The longer sides of void II are the same
(15.8 Å) in the four systems, while the shorter sides have various lengths ranging from
2.0 to 11.4 Å. Void III is inherent pores located at the center of the cyclic compounds.
The H-HexNet sheets stack without interpenetration to give porous LA-H-HexNets
(Tp-1, T12-1, T18-1, and Ex-1, respectively). Although the molecules give isostructural H-HexNets sheets, stacking manner of the H-HexNets depends on the molecular
structures (Fig. 11.8e–h). The void ratio of Tp-1, T12-1, T18-1, and Ex-1 calculated
by PLATON software with probe radius of 1.2 Å is 54%, 41%, 58%, and 59%, respectively. Aromatic solvent molecules used for recrystallization are accommodated in
the voids. The neighbored H-HexNet layers are stacked by weak interactions such as
face-to-face (π/π), face-to-edge (CH/π), and CH/O interactions. These weak interlayer interactions, as well as rotational flexibility of the peripheral phenylene rings,
allow Tp to yield at least four polymorphs of LA-H-HexNets including Tp-1 [56].
To investigate the structural changes upon removal of solvent molecules from the
void space, crystalline bulks of Tp-2Ds, T12-1, T18-1, and Ex-1 were subjected
to varied temperature (VT)-PXRD measurements as shown in Fig. 11.9, where Tp2Ds denotes the crystalline bulk of LA-H-HexNet of Tp because it includes either
or both of two polymorphic forms Tp-1 and Tp-2. The pattern of the as-formed
crystals at first showed almost no recognizable peaks, due to significantly low electron
I. Hisaki et al.
Fig. 11.7 C 3 PIs applied to construct HOFs
11.3.1 A Series of Cyclic π-Conjugated Systems
with Different Sizes of Macrocycles
C 3 PIs Tp, T12, T18, and Ex give H-HexNets structures via complemental H-bonding
between the carboxy groups (Fig. 11.8a–d) [55]. In the H-HexNet sheet, three kinds
of pores are formed. Void I has width of approximately 8 Å is formed within the PhT
motif. Void II has a non-regular hexagonal-shaped aperture. Its dimension is varied
depending on the size of the core of C 3 PIs: The longer sides of void II are the same
(15.8 Å) in the four systems, while the shorter sides have various lengths ranging from
2.0 to 11.4 Å. Void III is inherent pores located at the center of the cyclic compounds.
The H-HexNet sheets stack without interpenetration to give porous LA-H-HexNets
(Tp-1, T12-1, T18-1, and Ex-1, respectively). Although the molecules give isostructural H-HexNets sheets, stacking manner of the H-HexNets depends on the molecular
structures (Fig. 11.8e–h). The void ratio of Tp-1, T12-1, T18-1, and Ex-1 calculated
by PLATON software with probe radius of 1.2 Å is 54%, 41%, 58%, and 59%, respectively. Aromatic solvent molecules used for recrystallization are accommodated in
the voids. The neighbored H-HexNet layers are stacked by weak interactions such as
face-to-face (π/π), face-to-edge (CH/π), and CH/O interactions. These weak interlayer interactions, as well as rotational flexibility of the peripheral phenylene rings,
allow Tp to yield at least four polymorphs of LA-H-HexNets including Tp-1 [56].
To investigate the structural changes upon removal of solvent molecules from the
void space, crystalline bulks of Tp-2Ds, T12-1, T18-1, and Ex-1 were subjected
to varied temperature (VT)-PXRD measurements as shown in Fig. 11.9, where Tp2Ds denotes the crystalline bulk of LA-H-HexNet of Tp because it includes either
or both of two polymorphic forms Tp-1 and Tp-2. The pattern of the as-formed
crystals at first showed almost no recognizable peaks, due to significantly low electron